Method of sinking subaqueous tunnels.



0. HGH'. METHOD 0F SINKING SUBAQUEOUS TUNNELS.

APPLICATION FILED .TURB l, 19708.

Patented Dec. 22, 1908.

10 SHEETS-SHEET 1 INVENTOR WITNESSES.'

A1 1 URNEYS.

Patented Deo. 22, 1908.

10 SHEETS-SHEET 2.

` o. HOFF. METHOD 0F SINKING SUBAQUEOUS TUNNELS.

APPLIUATIOH FILED JUNE 1 1908. 907,357. l

i o. Hor?. METHOD OFSINKING SUBAQUEOUS TUNNELS.

APPLIOATION FILED JUNE 1,1993.

907,357. Patented Dec. 22, 1908.

10 SHEETS-SHEET 8 A TTORNEYS.

0. HOFF. METHOD 0F SINKING SUBAQUEOUS TUNNELB.

APPLICATION FILED TUHH 1,1903. v 907,357, rammed 1180.22, 190s.

10 SHEETS-BBBBT 4.

0. HOFF.V METHOD 0F SINKING BUBAQUBUS TUNNBLS.

AYPLIUATION FILED JUNE 1,1908. 907 357, Patented Dec.22, 1908. 10EEBBTB-SHEET E.

@a c) M v I@ WITNESSES: Y

INVENTOR ATTORNEYS.

0. HOFF. METHOD 0F SINKING SUBAQUEOUS TUNNBLS.

APPLIGATXON FILED JUNE 1,1903.

Patented D60. 22, 1908.

10 SHEETS-SHEET B4 IN VEN TOR WITNESSES.-

W om.

ATTORNEYS,

APPLICATION FILED JUNE 1,1908.

0. HOFF. METHOD of summe suBAQUBoUs TUNNBLS.

Patented 1380.22, 1908.

my?. www

ATTORNEi/v 0. HOFF. METHOD OY SINKING SUBAQUEOUS TUNNELS.

APPLIDATION FILED JUNE 1,1908.

Patented Dec. 22, 1908.

' 10 SHEETS-SHEET V A TTURNE V5,

O. HOFF.

MBTHOI) or SINKING sUBAQUEoUs TUNNBLS.

APPLIGATION HLBD JUNE 1,1908. ,357. Patented. DBC. 22, 1908.

10 SHEETS-SHEET 9.

R m m v m ATTORNEYS 0. HOFF. METHOD 0f SINKING SUBAQUI'IUS1 TUNNELS.APPLIGATION num mlm 1,1908.

907,357. Patented Dec. 22, 190s.

10 SHEETS-SHEET 10,

WITNEBSESZ OLAF illllil", OL1w 'lflltltY'lOVl/N, NEW YORK.

MElTHOD OF SINKING SUBAQUEOUS TUNNELS.

,u como?.

Specification of Letters Patent.

Patented Dec. 22, 1908.

Application filed June 1, 1908. Serial No. 55,904.

To all' whom it vm'ty concern:

llc it known thct l, OLAF HOFF, e4 citizen of the licitud Stews ofAmerica, residing et 'Ferry/'touw in. the county of Vliestcllestct' und51ste ol New York, have invented certain .of Sinking-j new und usefulimprovements in Methods Subaru u cous Tunnels, of which the is :ispeci'limition, reference boing im lo the eccinnpenying drawings.

follow! luid il:

y'l his invention relates to the construction ci' thot close ol'subiulucous tunnels, which are {crine-d by a series of jreconstructedtunnel tube sections built on s loro, launched mil llo ted to tiretunnel site und thon sunk iu pcsitlon thereon one alter uni'ither in etrench prepared to receive them.

My invention embodies certain improvements in the method of carrying outthe construction which is especially devised for the building of tunnelsacross navigable Waters wlicrc it is importent to carry on the Work`expeditiously und by such n method is will oli er the leest possibletern orary surface obstruction to navigation enV will also make itpossible to .carry the tunnel to no greater depth than suflices to avoidinterference with vessels passing thoreover.

Mv construction provides e tunnel built wholly of steel and concrete andrestin u on e. continuous foundation also pre emgoly built of steel andconcrete and forming an integral part of the completed tunnel itself. 'lhat part of the structure which is of steel is all constructed on lend`und consists of steel grids for the foundations .and of tunnel tubesections erich of which may be com osed .of one or more steel tubes ofseveral undred feet in length. ',lhe steel grids form part of an initialfoundation constructed upon the writer bed and upon this the tunnel tuboscctions ore sunk. i

ln sinking cach section to its prepared foundation upon the Water bed,water `is gradually let into the tube and the sinking is controlled bycir cylinders attached to the top of the section end adopted to supportlthewcight of the tube, or nearly so, in sinkings Alter the section issunk sind joined to the previously laid section it is embedded inconcrete and one of the novel features of my invention consists in soconstructing `the tunnel -tube section that it serves as c form for theconcrete, and in providing e continuousI foundation of concrete upon thewater bed. After one or more sections are thus laid, the wetcr isremoved from the inside thereof and l l l the linal step in thecompletion of thc tunmil muy be commenced by lining the tubes 'on theinside with concrete. To curry out all these different steps in theconstruction l employ special ineens und novel methods which precticsllypermit all. the work to be cerri'e( out with ordinary skillcd'leborunder ordinary working conditions, thus ovoidin all danger sind `risksincident to working un( er air pres' sure or other abnormal conditionsincident to other methods, all us more fully hereinafter described andshown in the accom )anying drawings, in which my invention is shown asapplied to e tunnel constructed of tunnel tube sections of the double ortwin tube type and embodying the structural features claimed in mypending application Serial No. 4280l3,\

filed April 20, 1908.

Figure 1 represents en end elevation of a tunnel tube section inposition for sinking, the dotted lines indicating its position afterbeing sunk: Fig. 2 is e 'longitudinal verticel section of Fig. 1,substentiall on line 2-2 and with. the tunnel tube section in the'pos-Ation shown by the dotted lines in Fig. 1: Fig. 3 is a cross-section of etunnel tube section in position upon the water bed and illustrating themethod of embedding it in concrete: Fig.

i show- 4 is s, sectional side elevation of Fi 1g. 5 1s a ing 4the shoreend of the tunnel:

longitudinal vertical sectionjhrough one of the air cylinders used insinking euch tunnel tube section: Fig. 6 is anendelevation of one ofthese air cylinders, showing, in connec-Y tion therewith, the mcensforsecuring it in position u on the tunnel tube section: Figs. 7 elevationsof the Ineens provi ed et the ends `of the tube sections for re isteringthe sections and also showing in igs. 7 and 9 in Yon 8, 9 en 10 aresubstantiell side and end cross-section the joint connecting .thesections: Fig. 11 is a, sectional lan view of the 'oined ends `of twintunne y Y ig. 12 is a. cross-section of the same o n the tube sections:

y loc line 12-12 of Fig. l1: Fig. 13 is a. similar 4 cross-sectionsubstantiallyin the plane of the joint and illustrating the method offilling the joint with cement: Figs. 14 and liillustrate in elevationand horizontal section the means by `which the twin tubes of a sectionare edjustaibly united: JFig. 16 is a. horizontel section through themeans used in adlition to that shown in Figs.`14 andl for tems, porarilyuniting' the twin tubes of eschsec tion: Fig. 17 is e plan view of thegrdused furthe tunnel foundation: Figvl 11s en end 25 ers.

35 and spaced from' the I i(55 by stifl'cning angles 5, Fig.

60 ,means at the ends together.

6h bottom ofthe elevation of the grid, illustrating also the l a channelflange 9 secured at the extreme method of sinkingit in position upon'the i end of the sleeye.

water bed, they dotted lines indicating the manner in which the tunneltube sections 5 are intended to rest thereon after the foundation is comleted: Fig. 19 is a cross-seetion through t e trench formin the tunnelsite and illjustrating the inetho of buildin `the foundation: Fig. 20is' a cross-section o l0 .the completed foundation and of a tunneltubesection supported in position thereon: Fig. 21 is an enlarged sideelevation of the concretingscow shown in Figs. 3 and 4: and

22 is a sectional end elevation of Fig. 21.

Fi Efhe tunnel tube sections may be made yseveral hundred feet in lengthaccording to the facilities for handling them and may be composed of oneor more tubes 1, the drawings showing two tubes, arranged parallel witheach other in accordance with the usual practice followed inconstructing tunnels for railwa purposes. The shell of each tube isforme of steel lates and constructed in the manner of built ing theshells of steam boil- For railway purposes, it ymay have a diameter of23 feet more or less, and may be formed of plates of an inch inthickness.

`The tubes are reinforced on the outside by a series of transverselyextending steel partitions ordiaphragms 2 reinforced at the edges by anle flanges 4. These diaphragiiis are space apart and inclosed betweenside walls 3, preferably formed of wooden sheathing scoured to thelateral edges of the diaphragms tubes thereby. 'lhe diaparagms areapproximately of rectangular shape, being preferably cut away at thelower corners to conform the side walls 3 more nearly1 to the slopingsides of the trench,

and they extend comlpletely around the tubes and form a level )asc forthe support of the tubes upon the water bed. They may be made in oneieee but preferably are ver- .ticall divided etween the tubes and se'cure to ether at their meeting edges, as will be more ully hereinafterexplained. In this Jnanner the tubes are set in an outer cradlelikeframe which imparts great structural strength and at the same timeserves as a form for embedding the tubes in concrete,

the intervals between the diaphragme forming a series of separatepockets. Half-way between each of the diaphragms the tubes are alsopreferably reinforced -en the inside 13, to which are removably attachedradial rods 6 as shown, the ends ofjthe tubes being similarly reinforcedto prevent deformation in handling.

Each section of tube is provided with for joining the sections Thesemeans consist of a sleeve 23'secured to and forming an enlarged socketat the end of one tule (Figs. 7 and 9) and fof vtwo rubi'er gaskets 7and 8, one seated von the socket and the other seated in The end of thesection to be joined thereto is adapted to enter the sleeve to the fulldepth of the socket, forming an annular s ace between it and the innerwall olfthe s eeve, and is provided with an outstanding fiange 10 at adistance from its end and a longitudinally projecting edge flange 11 atits extreme end, both so arranged that they cooperate with the gaskets 7and 8 to form two water tight joints when Ithe seetions are joinedtogether, suitable bolt holes being provided in the flanges 9 and 10 andgasket 8 for the insertion of bolts 12 to draw the sections together andpermanently unite them. ln this manner awater tight annular space isformed in the socket between ,the two joints and after' the sections areconnected upon the water bed this space is filled with liquid cement,provision for filling being ,made in the construction of the sections,as will be explained more fully hereinafter.

Provision is also preferably made to bolt the sections together on theinside after acis had thereto at a later stage in the con- Istruction,by securing angle bars 13 to the inner surface of the tubes at theirends and providing' bolts 14 passing through these bars. The spacebetween the angle bars 13 maybe calked if necessary.

ln order to insure an absolute and exact connection between the tubes,each tube is provided with one or more steel pilot pins 15 and'l (seeFigs. 7 to 1U) preferably placed one on top and one at the bottom. rl`hepilot pins are taper pointed and are adapted to guide the tubes intoposition. by entering sockets in the guide lugs 17, 18 provided on theends of the adjacent tribes. The guide lug 17 forms abell-shaped socketto guide the pilot pin 15 and the latter is provided with a ey way forthe insertion of a transverse key 24 to hold it in engagement with theguide lug. The pilot pins are provided with eyes 19 at the points forthe attachment of cables thereto as will appear more fully hereinafterand one or both may be dctaehably secured in lugs 20, 21 riveted to theend of the tube. To compensate for irregularities in the size ol' thetubes, the guide lug 18 is adapted to provide for a vertical pla f ofits pilot pin.

Provision is also made for theattaeliment to the tubes of transit rods22 (see Fig. 12), which are detachably secured in prescribed positionsand serve a well-known purpose in sinking the tubes.

Before each section is launched, the ends of the tubes are closed withtemporary bulklieads 25 (Fig. 12), to permit of the section beinglaunched and towed to the tunnel site, and water inlet valves 26 and airoutlet valves 27- are suitably placed in these bulkheads, the lattervalves being preferably adapted for connection with flexible hose 28 ass iown in Fig. 2` I also preferably place o grid preparcd for it, it issccurci scmhpartitions 2) iu ihr` upper holt' ol' thc i propcrtlcsiblepiping'controllori hvvnlws i3 tubos iutiruicdintc thcii' cnils undprovid@ 1 (sco FigV scparatc air outlots il() on top hctwccu tizi-sopartitions. Before :i` scction is launchml, the slto 'for it on thowater bod is pri-pared, rom"- incncing ot thc shore mid ot thc t|innol`Where the laying ol' thc .scrtious hcgins, by digging u trench ofsuitahhl dcpth lo prcvout the tunnel from foi-ruim: un obstruction tonavigation, und upon tin-` hotioin of this trench o suitable foundationil tllig. 20) is built for cach section.

In my construction `l providc initinliy, only for the Support of auchsection nt the middle and at the two ends, by sinkingr there 33constructcd of structural stool substantially as shown in Figs. 1T undiS. Sc cured to thisl grid und suitably distributori throughout itslength. :irc a nninbcr of anchor posts 34 and 35 projecting downwardlyVtroni it, thc nur-hor posti; l5 bring ol sulliciclit length to scrre :ispiles. "Ibis grid is built on hind und transported to thc tunnel sitewhere it is sunk thcrcon by suspending; it troin a ,si-ow H2, as shownin Figs. 1S and 19, the scow boing; hold in justified position by moansof anchors or s uds so hat the grid will bc dio ipod upon t ie exactspot where it is intcudi-dlto lic. By poundingP it down, the :rnrhorposts- I aro driven into the ground till the whole` grid lios at thcrequired lcvel allow thc water hed to sup iort at the pro ir height, thctubiVl scrtious wliich are inten( ed to lie` directly with the diahrnig'ms upon these grids. ily moons of t e saune scow, concrete is thonpoured through treniics 36 upon the Watir wd beneath the grid and intothc iutcrstices thcrcof till the whole grid is einhcdded, or partiallyso, within a solid [nass of concreti?. .instead of concrete, thefoundation only hc made by filling in with sand, gravel, broken stone orother suitable motorini und when so `illed in the foundation is thourcudy for sinking: the section thoreupon.

Whcn a. section has been floated to the site l in justified position byincluis oi suitable cables 38 and each tubo is than equipped with twoair cylinders 4l), see Figs. l und (i. which are supported in cradles 4]provided for them on top ot' the tubes and dct itchahly and adiustoblysecured thcrcin by strnps 4'2 attached to the diaphrngins of the tubos.Thc object ol' those nir uylindcrs is to sustain ly thcir buoyantx', thencigrht of the tubes when snlnncrgcd and illod nith .rntcr, :1o thatth(` tubos will not hc mcrstrnincd nt any joint, or joints sprung duringhandling, canning looks. 'ihcsc cyli.` ders nrc prouortioucd accordingto the vigili thor will have lo support in sinking .-uul thcir buoyancyis udjustod by means of lettinor :rtcr into thciu or blowing witter outoi thornY (Enopresscd .wir is uscd for thispnrposc rind the cylindersure equipped with lliich rylindcr is prcllcrubly diridcil by' billihouds4-1 into a control und two cud cinnpurtrlnonts, tho controlcomportnicuts boring :YL writer admission volw yi5 in its` uudcrsidowith n volvi' toni cxtcnding ont, through thc top.

lil-Yiwu util is rt-ndy t'or sinking, wirr' roiacs ttl Ehio* E711 :rrrliislouod to thil orcs iu thil pilot pins nud par# d donn hy dircro toth-i rnd of tin` tubos olrrody souk ond rino'rvtcd iii, [lloro theropita nrcpiisscd through thc sirio clsA in thc guidi` lugscorrcspoudiiu: to thepilot linns, lhcncc over suitable pulleys (notchoirni i'ustcncd to the tubos ucar thc guido lugs und up through the7rotor to Winches on thc scow, all boing so arranged that thcsc ropes iuconnection with suitable lines sorurcd to thc outer end ci' the sectionobsohit-cli' control the cucinino movement in sinking.

Tho sinking of thc scction may be carried out with the oid of n singlecow fill, by first opening the inlet Valves 2) at the` bottoni oi thebulliheiids 25 in the tubes and likewise opening, the corresponding oirvulves '27' at the to i oi'4 the bulkhcuds. Water is thus let in mr' theoir let out, causing the tubos to gradually settle down in the writer ata spoort dependent upon the inflow of the Witter, and are thereforeunder perfect control. As soon as the water in the tubos riscs liighenough to reach the souri-partitions Btl the zur in the top of the tubesbetween said unrtitious und the bulkheads becomes trapped and byproporly manipulating the valves controlling the escape of the nirtherefrom the couiliiu'iutn of the tubes is readily maintained und noplunging can occur. To thus control the tubes during their entiredescent valved hose 28 may be attached to the oir outlets 2T undmanipulated troni floats or scows overhead, (sec lig. i2). By permittingthe confined nir in the tubes to thus gradually escupe under control ofthe oir valves, the tubes continue to slowly sink until caught up by thcair cil inders. Those cylinders bring adjusted, as prcviousiy described,to sustain the weight oi the submerged tubes to within n small nnirgin,soy 10,000 pounds, ut noch ond, the tubes irre readily uphold, troc tohe raised or low cred, by moons of two lines 4S (sec Figs. 1 und i!)from suitnblc derricks on tho con ttl rocurcd alongside. The sinking oi'the tubos is thus accomplis-bod in u simple nniuner nud under absolutocontrol with tin` tubos evenly balanced and not overstroined nt anypoint. llovrcvcr, sonic otc thc provisions hcrciu unido for the sinkingof the tubes may hc omitted its circumstances may n'nrrnnt. all ot'which may be left to the discretion oi the engineer in charge.

As thc tubes .sink to the` water bed, thc lines 46 uttochcd to thc pilotpins nrc talon) up and thc section is landed on thc prcparcd foundation.By pullingr in on these lines the section is moved toward the one towhieh it is to he joined till the tubes are in proper eugageinent formaking the eonueetions. A

diver then secures the seetion l'roin inoving endwise out of engagement,hv driving the wedge l\'e \s .24 into the pilot pins lo, und the tuhes:ire then brought into proper :dinemeut hv menus of the transit rods 22.When the :t iueineut olE the set-tion is au'eomplished, the diver willinsert the holts l2 through the tlftnges G nud it), holtiug theolilrnllv to.. gether, und insert the ueressin'v shhns under thediuphrftgms to lorm ou :ibmlule even hem-ing it all points where thetoundzition is provided. The oir cylinders -ltt :ire ne.\. permitted tograduali)r l'll with witter, this etnising the weight of the tubes|ipported h v them to be gradually trmisl'erred lo the louodntion, undsliiekening the lmuds 4L so llnit they may he diseonneeted to relezee evliuders which muy then he lloaited to the top lrv expelling the waltertherel'roio` The sinne oir elvliuders mov he used l'or eurh succeedingseetiou.

sluiting" i is proposed to do this by means of trexnies 5S :nid whiehseow is :1s shown in Ylt`igs. and 4 wherein 57 re resents :i seow fromwhich tho Work is tone anchored transversely of the sunken tubes in sucha nuinnor that its position nur v he readilyY shifted :is the workprogresses. 'l'his seow is provided with spuds .'itl to hohl itstenti",v ngtiinst wind. :ind

r w .ives und eurries o suitable. outiit l'or hoisting the rmi omterizilon hoord into suitable hius t'il und tor mixing und dellvering theront-rete to the tremies ol' whieh there are the :tir

Although the two tuhes ol' eireh seet iou :ire l preferably eonneeted:rnd sunk :it the sione time, still ill ronsidered more expedient the \vmay he sunk one :it :i time. ll'sunlv' in puirs` it is iidvisaihlo tomuy he adjusted ence to the other within o lew ilu-hes ol"` movement totheir length` provided l'or its shown in Figs. I4 :ind l5 meansolpintles 52 passing through spin-ed knlu'hles 53 secured to thediitphrnguis :it their meeting edges, any suitohle number ol' sueheonneetions being provided. 'l he diziphrfignls muy also ho temporarilyseeured together :it :L number hollts 54 (see Fig. Y [hinges on themeeting edges ol' the diri-- phriigms, suitnhle sparing hlorhs beinginterposed where neeessznv. 'these provide l'or any diil'erenee in undthis ndjustulent univ he i sund, eher, st ol pierres hy lnetins ol i lt)through the :ingle lutter l l'astenings will be removed hel'ore sinking,

but where the sections have heen previrnisliv 'fitted together on hindthis will not he neeesssn' 'lVhen the ends ot the tulle seetions havebeen holted together as deserihed, the joints nre tested to ascertainwhether they are tight, by providing the sleeve 23 ol eiteh joint,before sinking, with two flexible eon neotions 56, :is shown in Fig. 13,which oonnections lend to the scow lloziting above. With a l'oree pumpattached to oneronneetion and the other closed, water is forced hy thepunip through the annular space within the sleeve, -und thus thetightness ol' the oint readily ascertained. When the joints have beenlound reasonably tight, pure cement grout is then pumped into theannular space through one of the connections until it three, enehsupplied with its own mixer 64. These trennes nre ol suitable length toreach `down to the bottom ol' the trench and il neeessiirv the lowerends tire Inode llexihle, :uid the)v :ire hung on the sides oll the snowI'rom srnll'olds (i5 on whieh theviv ure raised as the work olrouereting progresses, suitable provision being mode Ior delivering theeonerete thereto nt :my required height.

With suitnhle eure in the handling ol' the tre|nies the eonerete min hedeposited at n eonsiderohle depth h v keeping their lower ends :du :rvswell innnersed in the outllowing ront-rete, the walls ol' the pocketskeeping the so eonneet them thor one i longitudumllv wlth relerwaitertrom wushing out the rement. As porliet :dier poehet is thus lilled, theloundzition will he eompleted :it the sinne tinte, sim-e in thosepoekets whieh :ire not above the initial iouudaitiou the eonerete willbe deposited right upon the bottoni olI the t reueh.

Hiinultinieousiy with the depositing ol' the ront-rete, the spzuebetween the side wit-ils 3 :uid the treni-h sides indy he lilled in withone or other suitable uutteriolJ the ehnrneter oll this hoek fillingdepending hugeliv upon the surrounding conditions, or in sonne phu'esthe wash olthe river may he relied on to lill in these spores.

.\s it is neeesszlriY to lesive :in opening in the ensiug or side wzills:it tho ends ol' the tuhe sertions lo provide net-ess lor the divernothing the eonneetiou, gutes (itl (Fig. 11), :ire provided to closethese openings, braces ti] being also prov ided to strengthen thooftsing at these points.

ln order to mathe the connections ait the shore ends ol the tunnel, apocket is dred ed into the hindi or shore and when the tues halve beensunk and eonereted in, the shore end thereol' is inelosed within :1.coller dann or seziwnll o2Y :is shown in Fig. 4. The pocket is thenpumped out and used si working slud't l'or lining the tubes beforemaking final eonneetion with approach tunnels. T0 permit w ork on theinner concrete lining to he eommeneed :is soon is possible, thebulkheztds at the shore ends of the tubes and one in every other tuhesection should be built comes out through the other connecver Y heavyand water tight so as to be Capable of resisting the full waterpressure, the other bulkheads need not be so heavy. Through suitablevalved apertures provided in these heavy bulkheads one section afteranother may be emptied of the Water and the bulkheads removed to giveaccess to the section beyond.

This particular construction of steel tubes and the manner in which thejoints between the sections are made, practically eliminates thepossibility of leakage, and the general scheme of. construction is suchthat the use of compressed air is dispensed with, eliminating itsdangers and disadvantages and the necessity for the installation of anexpensive laut.

While the construction of the tunnel as herein described and shown inthe drawings is primarily devised for navigable waters and hasfbeenspecifically designed for the tunnel under present construction acrossthe Detroit river, it is adapted to meet the general requirements, andits structural features are ada ted to be used wherever the open trenchniet od` of building tunnels may be applied. It is also obvious that theconstruction may be variously modified within the scope of my inventionto suit prevailing conditions. Thus any other suitable foundation may beused in comiection with the other features of Jmy invention and my planof providing a foundation of concrete may be` variously modified asfor-instance by omitting the initial foundation under the middle of thetube and then after the tube is laid by first filling in the space belowthe tube with concrete at one or more points intermediate the ends andallowing the concrete to harden before proceeding with the embedding ofthe tube.

The advantages of my construction in cost, safety and generalapplicabilityto meet the requirements will be Well understood by thoseskilled `in the art, none of the steps in the construction involvin anydifficult engineering problems and t ie equipment required being easilyprocurable and representing but a small portion of the cost ofconstruction.

Havin thus fully described my invention What Ic aim is 1. In subaqueoustunnel construction the `herein described method of laying a tunnel tubeor a section thereof Which consists in constructing the same on landwith au outer supportin frame adapted to form the sides,

ends and, ivision Walls of a forni for embed.- ding 1t in concrete, thedivision Walls dividing the form transversely' into compartments,excavating upon the Water bed a trench, the bottom of Which is below thelevel required for supporting the tube, constructing upon said bottom a.foundation adapted to support the tube upon the required level,

sinking' the tube upon Asaid foundation and then embedding it inconcrete by introducing `each section being conne the material intolllf'` compariments formell by the outer fl amo 2. The method ol' layingsulmzliwous tunnel sections which consists in constructing the metallicportion of the tunnel tubiou land intemporarily closed ronnvflililvsor-- tions with an outer l'l'anie or eindhadapted to serve as a formfor embedding the sor-lion in concrete, dredging out n section o." theivatcr bed of tl-o tunnel-silo, Laying a. foundation upon the excavatedsito ai. intervals, laying the first section of .the lnnnfl tube uponthe prepared site, en]liedllinuj it in concrete and silnultaneously buehlilling the ser tion, and then adding other like sections successivelyin the saine manner.

3. The method of constructing suhaqueous tunnels in sections, whichconsists in con` st'ructing the'inetallic porion of the tunnel tube onland in temporarily closed connectible sections each having an outertraine or cradle adapted to serve es a form for embedding it inconcrete, preparing 'the Waterbed for the shore end section of thetunnel, laying the initial tunnel tube section upon said ter bed,embedding it in coin'fretc-, succo..- sively adding other sections inlike manner,

d tothe previously laid section, then constructing a workA` ing shaft atthe shore end of the tunnel and completing the tunnel by cstalglisliingconnection between said working shaft and the interior of the tunnel. f

4'. The method of constructing subadueous tunnels of the character desc'fc-ed, which consists in dredging out a` sectionof the Water birdbeginning at the shore end. of the tunnel site, laying upon said bed atintervals a foundation, sinking upon said foundation a section of ametalllc tunnel tube temporarily closed by bulkheads and having an outercasing or frame adapted to su port it upon the foundation and serve as agarni for embedding it in concreto, embedding the section in concrete,continuing in like manner to add other sections of the tunnel tube, andcompleting the tunnel by constructing a Workingl shaft at the shore iend of the tunnel and establishingr con nec-tions with Athe interior ofthe tunnel tube.

5. The method of constructinnr subaquc'- ous tunnels of the character.lescribed, which consists in constructing a section of metal tunneltube With an outer casing or frame adapted to serve as a forni forembedding it in concrete and having` the ends Yteinporarily closed withbulkheads, excavating a il (l trench in the water bed corresponding tothe length of the tubo section, laying upon the bed of the trench atintervals a foundation of concrete with metal grids embedded therein,laying upon said prepared foundation the metal tube section, embeddingthe same in concrete and simultaneously therewith back filling thetrench, successively eonstructing other tunnel tube sections andproceeding in like manner to lay cach section.

6. The herein described method o providing a foundation in theconstruction of tunnels ot. the character described, which consists inirst excavating a trench in the water bed eoirespoiuling in length tothe length ol the section to be laid in it, sinking upon the bed ofsaid` trench one or more metal grids having downwardly projeetinffanchor posts adapted to support the grin at variable heights above thebed of the trench, adjusting said grid or grids to the required levellor supporting the tunnel sei-tion to be laid thereon and then embeddingthe grid or grids in concrete.

7. The herein described method of Sinking a tunnel tube section upon thetunnel site,wliieh consists in closing,r the ends with removablewatertight bulkhead's, floating the section to its proper location andmooring it in position thereon, securing upon the Section at oppositeends air cylinders proportioned to support by their buoyancy the weightofthe section when submerged and illcd with water, sinking,r the t-ubeby admitting water into it and permitting the air to escapo till thesei-tion is submerged and sup ioited by the air cylinders, and thengradually lowerirwr it to the water bed by the aid of suitabc hoistingtacklefrom a scow liioored alongside, the buoyancy of the air cylindersbeine,r simultaneously reduced till a small fraction ol' the weight issustained by the hoistingr tackle.

8. The herein described method of sinking a tunnel tube section upon thetunnel site, which consists in providing the tube with removableWater-tight bulkheads at the ends and with senii-partitions on topintermediate the ends, floating the section to its proper location,mooring it in position thereon, securing` upon its opposite ends aircylinders proportioned to support by their buoyancy tie weight of thesection when subnierged and lilled with water, causing the sect-ion tosink by admitting Water ipid simultaneously maintaining its equilibriumby controlling the escape ol the air from the space between the bulkheads and the semi-partitions lill the .seetion is subnicrginl andsupported by the air cylinders, and then lowering the `section upon itswater bed under control of suitable hoisting tackle l'roni a scow mooredalong side, the buoyancy of the air cylinders being simultaneouslyreduced till c, small portion of the weight is sustained by the hoistingtackle'.

9. The herein described method of constructing tunnels in sections;which consists in successively constructingT the tunnel tube inbulkheaded metallic sections with conncetible ends, one of which titsloosely into the end of the other section and forms a Water-tight'ointthcrewith when the sections arc tig illy drawn tovether, inexcavating a trench in the water icd'and laying a foundation thereon,floating the initial section to the tunnel site and mooring it inposition thereon, sinking it upon the water bed with air cylinderstemporarily attached thereto and supporting by their buoyancy thcgreater portion of the weight of the section, removinor the aircylinders after the section is brought into justified position,permanently securing it to the Water bed by embedding it in concrete,and then continuing to construct and sink other li ht sections in likemanner successively, eac section being sunk in close proximity to thepreviousl hau ing lines laid section to thereto in guiding relation,

passing from the `previously laici section and connected thereto by4 thesection to be` connected` 10. 'the method of con'struct'ing subaque-4 lwhich consists in conous tunnels in sections,

each section with an strueting the tube of outer frame adapted to suport the tube out of contact with the water ed and servo as a form forembedding it in concrete, excavating a trench in the water bedcorresponding to the length of the nieta] tube sction, laying atintervals upon the bottom of the trench a bed of concrete, laying themetal tube section upon said bed `and then embedding the whole tube inconcrete by means of tremies vertically adjustably suspended from a.working scow moored above the section and of a length adapted to reachthe bottom of the trench.-

l1. The method of constructingsubaqueons tunnels in sections whichconsists in constructing the metal tube of each section with an outerframe adapted to support the tube out of contact with the water bed andserve as a form for embedding it in concrete, excavating a portion ofthe water bed to form a trench to receive the section, layin atintervals upon the bottom of the trenc a bed of concrete with steelgrids embedded therein laying the tube section upon this prepare bed andthenv embedding it in concreto by means of treniiesvertieallyfadjustably sus-y pended from a working seow moored above thesection. and suitably equipped for mixing the eonerete'on board the scowand deliver ing it tdthe'treinies.

l2. The method of sinking a buoyant tun'- nol tu be section to the waterbed, which cdnsiste iii temporarily attaching upon the section aircylinders adapted to support by their buoyancy the weight of the sectionwhen l, suhinerging the tube till it is supported by the air cylinders,admitting water into the tube and simultaneously controlling its sinkingby controllin the escape of the air from portions of said tube formedinto separate air chambers,v then gradually re ducing the buoyancy ofthe air cylinders and controlling the sinking of the section bygradually lowering it with hoisting tzielile on a working scow mooredalongside, the seetion being sunk upon si prepared foundation upon whichit may be drawn into justified position while bein(y held under eontrol.

13. The herein (eseribed method oi' eonstrueting subiiqueous tunnelswith preeon i structed tunnel tube sections which consists i 1n firstpreparing :i waiter hed for the section to be loid upon ii` lower levelthun the one upon which the section is to be lured und eonstruetiiigupon siiid waiter bed more points foundations adopted to sup )ort theseetion thereon at the desired level. in

preoonstrueting the section to be laid thereon with iin outer frameadapted to serve in eolineetion with the prepared waiter bed ns ii lform for embedding the tube, sinking the section upon the preparedfoundations nnd adjusting it thereon in osition sind thence completingthe foundation :ind embedding the tube b i' introducing the iiniteii-.iltherefor into the forni.y

ln testimony whereof l uliix my signature iii presence of two witnesses.

OLAF HOFF.

vit nesses:

()'rro F. BARTHEL, A. .\l. Donn.

